Assessment of Heavy Metal Concentrations in Smoked Catfish (Clarias gariepinus) and Grasscutter (Thryonomys swinderianus) from Ondo State, Nigeria

Abstract

Fish and meat are classified as a protein food source, important for tissue building and repair and very protein and a major part of a nutritional meal. This study assessed the concentrations of iron (Fe), manganese (Mn), nickel (Ni), cadmium (Cd) and chromium in Clarias gariepinus and Thryonomys swinderianus, estimated the daily intake (EDI), target hazard quotient (THQ) and hazard index (HI) of heavy metals in the fish and bush meat and; compare the obtained concentration level with the World Health Organisation (WHO). The digestate of the C. gariepinus and T. swinderianus was examined for heavy metals using the Atomic Absorption Spectrophotometer (AAS). The results showed that Fe in the fish ranged from 149.0±7.762-155.0±5.099 mg/kg, while that of T. swinderianus ranged from 115.0±2.160-117±2.450 mg/kg. The concentrations of Fe exceeded the WHO limits of 100 mg/kg. The concentrations of Mn in C. gariepinus ranged from 1.0±0.817-2.0±0.817 mg/kg and in T. swinderianus from 2.03±0.817-3.00±1.414mg/kg. The result also exceeded the Mn limit of 1 mg/kg and 0.0094mg/kg. Nickle ranged from 0.00±0.00-1.00±1.414 mg/kg in fish and while in grasscutter, the concentrations were below the equipment detection limit of 0.008 mg/kg. The concentrations of Cd and Cr were below the equipment detection limits of 0.0028 and 0.005 mg/kg. The average EDI in both adult and children in fish and grasscutter in Fe and Mn were higher than their reference doses of Fe 0.007kg/person/day and 0.00014kg/person/day respectively, also the order of EDI in both fish and grasscutter was Fe>Mn>Ni>Cr>Cd. The THQ and HI values were less than 1, implying no carcinogenic effects on the consumers. This study concludes that heavy metal pollutants were detected in the smoked fish and grasscutter but recommends further study on the same site, as well as enlightening the fish and grasscutter sellers on the nature of materials that are suitable for smoking and the health risks associated with heavy metals.